Q. I am thinking about buying a 200-gallon pond for the back yard and stocking it with seven Chinese lionhead goldfish. Is there a better goldfish for ponds? How big do they grow and will the pond be big enough for them? I live in British Columbia where it gets very cold in winter. Will they need a heater? Also, what type of filter should I use?

A. Lionheads — a variety of goldfish with puffy oranda-like heads, no dorsal fins and a double tail — are wonderful goldfish. In my experience they are inordinately friendly, easily trained and always fascinating to watch. Good specimens are also expensive. So, from a purely "goldfish" perspective you cannot do better.

They will live long and grow quite large under the right conditions. A goldfish that thrives for 20 years or more is one that was properly kept. And a length of 8 inches or more is not uncommon. Personally, I would not put more than four in a 200-gallon pond — which is what I meant by the right conditions. Putting more in the pond will limit growth and produce less than optimal development.

Do not mix other varieties of goldfish with your lionheads. Because all goldfish can, and do, interbreed, I think it makes sense to keep the bloodlines separate — especially for prized goldfish like lionheads. Moreover, most other goldfish varieties (except for celestials and bubble-eyes) can out-compete lionheads for food. There is nothing more unattractive than a thin, sickly lionhead goldfish.

Because your pool is so small be sure not to place it where it gets too much sunlight. Remember, goldfish, are coolwater fish. Too much summer sun could overheat the water. Some kind of shading — even lily pad coverage — will be necessary.

Will your lionheads need a heater for winter? No, they'll need ice picks! There is no way you will be able to keep fish alive in a shallow 200-gallon pond over the winter. It will almost certainly freeze solid.

Moreover, lionheads are quite sensitive to cold water outdoors. I recommend not letting water temperatures drop below 55 degrees Fahrenheit for these animals.

You must either plan to heat the entire pond to the mid 50s or plan to take the fish indoors during the winter. If you have a basement or storage room that stays cool you might consider setting up a 100- to 200-gallon pond to hold them. This could be a simple box and liner setup, two children's wading pools or a spare 125-gallon aquarium (which, of course, we all have lying around the house).

Which brings us to your filter. You will definitely want a recirculating system of some kind. For your size pond (and considering the need to bring the fish indoors) I would suggest a Tetra Pond Luft pump. This air-pump/foam-block system works well on my 300-gallon indoor pool. It is very effective at mechanical and biological filtration, very energy efficient, quiet, easily moved and is also easily maintained. When fall rolls around you can just bring it indoors to provide uninterrupted filtration.

Aphid Aggravation
Q. First off, I would like to thank you for the advice about raccoon problems you gave me. I enlarged my pond from 75 gallons to about 1000 as you recommended, and since then have had no raccoon problems at all. Now I have a new problem: aphids.

One day I was at a local water plant supplier and I saw that they have the same problem with their plants. We both have little black bugs speckled all over our water lettuce and water lilies. I asked what these bugs were and they said aphids, but they did not know how to get rid of them.

These little bugs have complete control of my plants and they make my pond look ugly. None of the methods commonly used to control aphids would be safe for use in my pond.

A. Not only did you get rid of the raccoons, but you solved another problem by enlarging your pond from 75 to 1000 gallons. Your pond will maintain a much higher quality of water for longer periods of time without any work on your part. pH, oxygen, temperature and pollutant concentrations will all be much more manageable now.

Yes, the black bugs are aphids, and they are easily transported on aquatic plants. These little aphids are called blackfly aphids. They can be controlled by simple hosing once or twice a day. A good strong spray across and under leaf surfaces will knock them into the pond. Having a few insectivorous fish, such as mosquito fish or orfes, will help because they will eat the aphids in the water.

This approach also has the effect of adding fresh water to the pond, aerating the water surface, clearing plant leaves of dust and is also completely nontoxic. In addition, it gets you out to the pond once a day to see what is going on. No insecticides are safe for use on the pond.

These particular aphids apparently spend the cooler winter months on cherry trees and plum trees. So, if you have some in your garden you might consider using an oil spray over the winter to reduce the population. Just do not spray near the pond.

What Are They?
Q. We have a small, 1500-gallon spring-fed pond in our wooded backyard. We planted it heavily with water lilies, irises and lots of other bog plants. We also have three goldfish just to eat bugs and algae.

The reason I'm writing is because last year in April we found several large balls of jelly attached to underwater twigs. They were clear, about the size of a tennis ball, and had hundreds of little embryos inside. They were gone by late may, but we don't know what they were. Were they frog eggs?

A. I love letters like this. The great thing about outdoor ponds is that they always offer the unexpected. As I have been trying to point out in this column for the last couple of years, plants and fish are only small parts of the natural design of ponds. Your experience just reinforces the message.

The jelly masses you found were salamander eggs, almost certainly spotted salamanders (Ambystoma maculatum). These delightful animals spend almost all of the year underground (hence they go by the generic name "mole" salamander). They come up only once a year, in early spring, to breed. They seek out temporary woodland ponds — an increasingly rare type of wetland called a vernal pool — find a mate and breed. Within a few days they return underground.

Spotted salamanders may be 6 to 9 inches in length. They are chunky, attractive creatures, and have no teeth. They usually start to breed at about three years of age and may live for another 10 years or more. Although they can travel a mile or more to a breeding pool, the chances are very good that your salamanders are within a few hundred feet of your pond.

The eggs hatch after two months (depending on water temperature) and the larvae spend the next month or two in the pond eating whatever they can get their mouths around — including each other. Then, one day, before fall comes, they march out of the pond and their gills drop off. Their aquatic life is over.

If you want to catch a glimpse of these guys your best chances will be early spring. On the first night when air temperatures rise above 42 degrees Fahrenheit and it is raining or misting heavily, walk out to your backyard (after 10 p.m.) and scan around your pond with a flashlight. You will see these jet black, yellow polka-dotted animals. Be careful when walking around the pond because they walk over land to reach the pond.

If you have spotted salamanders freely breeding in your pond you must be doing a great job in maintaining natural pond qualities. Development is rapidly eliminating the breeding pools of these creatures, so your pond is now also a refuge.